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Nuclear Theory·nucl-th

Wednesday·November 9, 2022

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 01

    [Submitted on 8 Nov 2022]

    Neutron skin of Al with Skyrme and Korea-IBS-Daegu-SKKU density functionals

    Hana Gil · Chang Ho Hyun · K. S. Kim

    Recent measurement of the parity-violating (PV) asymmetry in the elastic electron scattering on Al target evokes the interest in the distribution of the neutron in the nucleus. In this work, we calculate the neutron skin thickness () of Al with nonrelativistic nuclear structure models. We focus on the role of the effective mass, symmetry energy and pairing force. Models are selected to have effective masses in the range where is the nucleon mass in free space, and stiffness of the symmetry energy is varied by choosing the slope of the symmetry energy in the range 9.4 -- 100.5 MeV. Effect of pairing force is investigated by calculating with and without pairing, and using two different forms of the pairing force. With nine models, we obtain fm. The result is independent of the effective mass, symmetry energy, and the form of pairing force. However, is negative when the pairing force is switched off, so the pairing force plays an essential role to make positive and constrained in a narrow range. We also calculate the PV asymmetry () in the elastic electron-Al scattering in the Born approximation at the kinematics of the Qweak experiment. We obtain a very narrow-ranged result (2.07 -- 2.09) . The result is consistent with the experiment and insensitive to the effective mass, symmetry energy and pairing force.

    Comments:
    5 pages, 2 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2211.03948 [pdf]
    Mod.Phys.Lett.A(2024)·1 citation
  2. 02

    [Submitted on 8 Nov 2022]

    Electromagnetic fields in ultra-peripheral relativistic heavy-ion collisions

    Jie Zhao🇨🇳 · Jinhui Chen🇨🇳 · Xu-Guang Huang🇨🇳 · Yu-Gang Ma🇨🇳

    Ultraperipheral heavy-ion collisions (UPCs) offer unique opportunities to study processes under strong electromagnetic fields. In these collisions, highly charged fast-moving ions carry strong electromagnetic fields that can be effectively treated as photon fluxes. The exchange of photons can induce photonuclear and two-photon interactions, and excite ions. This excitation of the ions results in Coulomb dissociation with the emission of photons, neutrons, and other particles. Additionally, the electromagnetic fields generated by the ions can be sufficiently strong to enforce mutual interactions between the two colliding ions. Consequently, the two colliding ions experienced an electromagnetic force that pushed them in opposite directions, causing a back-to-back correlation in the emitted neutrons. Using a Monte Carlo simulation, we qualitatively demonstrated that the above electromagnetic effect is large enough to be observed in UPCs, which would provide a clear means to study strong electromagnetic fields and their effects.

    Comments:
    5 pages, 4 figures, published version at NST
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2211.03968 [pdf]
    Nucl.Sci.Tech.(2024)·32 citations
  3. 03

    [Submitted on 8 Nov 2022]

    A Toy Model for Low Energy Nuclear Fusion

    Kaanapuli Ramkumar · Harishyam Kumar · Pankaj Jain

    We study the fusion of a proton with a nucleus with the emission of two photons at low incident energy of the order of eV or smaller. We use a step model for the repulsive potential between proton and the nuclei. We consider the reaction both in free space and inside a medium. We make a simple model for the medium by assuming a hard wall potential beyond a certain length scale. This essentially leads to discretization of the energy spectrum which is expected inside a medium and is seen both for a crystalline lattice structure and for amorphous materials. We use second order perturbation theory to compute the transition rate. We find that the rate in free space is very small. However in medium, the rate may be substantial. Hence, we conclude that nuclear fusion reactions may take place at low energies at observable rates.

    Comments:
    Submitted to Pramana
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2211.04008 [pdf]
    Pramana(2023)·6 citations
  4. 04

    [Submitted on 8 Nov 2022]

    Study of structure and radii for Na isotopes using microscopic interactions

    Subhrajit Sahoo · Praveen C. Srivastava · Toshio Suzuki

    In this work, Na isotopes with mass varying from 20 to 31 have been studied using DJ16A, JISP16 and N3LO microscopic effective interactions in the -shell. These effective interactions are derived for -shell using no-core shell model wavefunctions and a unitary transformation method. We have also performed calculation with IMSRG effective interactions targeted for a particular nucleus. The studies include a detailed analysis of ground state binding energy, low-lying spectra, and electromagnetic properties such as reduced electric quadrupole transition strengths, quadrupole and magnetic dipole moments of the Na chain. The results obtained from these microscopic effective interactions were compared with the experimental data as well as with the results of phenomenological interaction USDB. The charge radii of Na isotopes are evaluated using shell model harmonic oscillator wave functions. In addition to charge radii, matter radii and neutron skin thickness in the Na chain are discussed with a focus on neutron-deficient Na isotopes.

    Comments:
    26 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2211.04133 [pdf]
    NPA(2023)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE